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Thread: Question on how this works?

  1. #1
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    Default Question on how this works?

    public static void mystery(int num)
    {
     if (num > 0)
     {
     mystery(num  1);
     System.out.print(num + " ");
     }
    }
     
    mystery(4);
    System.out.println();

    I was looking through my older notes from a class I took a few years ago, and it was saying the answer was 1 2 3 4 is what outputted when this is run. I would think it is 4 3 2 1, and I don't understand how it is the other way around. Would anyone be kind enough to explain what actually happens to make it 1 2 3 4? Thank you.


  2. #2
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    Default Re: Question on how this works?

    Quote Originally Posted by sammythesp3rmy View Post
    Would anyone be kind enough to explain what actually happens to make it 1 2 3 4? Thank you.
    The print is after the recursive invocation of mystery. The last deepest invocation is with 0 but since there is the condition num>0, no recursion and no print happens. Then gets one step back, where the invocation was with 1 and print it ... and go back where was 2 .....
    Andrea, www.andbin.net SCJP 5 (91%) SCWCD 5 (94%)

    Useful links for Java beginners My new project Java Examples on Google Code

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